Tag: circadian rhythm

Many health and nutritional experts say that breakfast is the most important meal of the day, but I beg to differ. Let me draw your attention to the period of time that precedes that meal. A time that should be spent in a state of deep restfulness. Doing without this form of nutrition will set your body up for certain demise. Sleep is the meal that should never be skipped.

Our appetite for sleep is programmed into a part of the brain known as the hypothalamus, which is the regulating center for the various biological drives that keep our bodies functioning. When we are infants, the part responsible for sleep and wakefulness is out of control. Think of how many babies sleep all day and are up all night or those that have short bouts of sleep spread out over an entire day. The reason for this insane sleep schedule is the immaturity of the internal clock that sets daily functions to the rhythm of 24 hours. Human beings have it, as do plants, animals, fungi and certain bacteria. Dubbed our Circadian Rhythm, sleep and wakefulness is dependent on exposure to light and dark. The first few months of life are pivotal in establishing this internal rhythm, but some babies take as long as a year to sleep a solid 8 hour night. Once the rhythm is established, your body will function on a 24 hour cycle. When in the presence of darkness, our brain’s pineal gland, which is light sensitive, produces a hormone melatonin that helps to make us sleepy. Desire for sleep is strongest during the darkest hours between midnight and 6 a.m. and to a lesser extent in the mid-afternoon. In American culture, this is the 2-4 p.m. slump when most people grab themselves a coffee and/or some kind of energy boosting snack. In Europe and Latin America, this would be your afternoon nap-time otherwise called the “siesta.”

National Nap-time is the right idea! (Image of the first ever Sleeping Championship in Madrid, Spain 2010)

Sleep itself is a highly involved process consisting of 4 stages that each have a physiological affect on the body and brain. The first three stages are part of what is called Non-REM or quiet sleep, a state where thinking and most physiological activities slow down, but movement can still occur, and a person often shifts position while sinking into deeper stages of sleep. Unless something disturbs the process, people will pass through these 3 stages of sleep smoothly. The fourth stage of sleep is called REM or dreaming sleep, a state where the brain is very active, but the body is paralyzed. Normal sleep cycles alternate between quiet and dreaming, with most deep sleep occurring in the first half of the night. During the second half of the night, dreaming sleep gets much longer and alternates with the second stage of quiet sleep. More on these stages now…

During the first stage of sleep, dubbed drowsiness, your brain no longer receives visual stimuli from your shut eyes, body temperature begins to drop, muscles relax, and eyes often move slowly from side to side. Although you may start to lose awareness of your surroundings, you can very easily be awakened. In the second stage of sleep, known as light sleep eyes remain still and breathing and heart rate are much slower. The brain starts to show irregular electrical patterns of slow waves and short bursts of activity. The brain can also respond to outside stimuli, like someone whispering your name, which scientists believe could be a built in vigilance system to ready you for awakening if necessary. Half of a good night’s sleep is spent in this stage. Once you enter the third stage of sleep, known as deep sleep, your body undergoes some important cellular changes. Blood flow to the brain decreases and it stops responding to outside stimuli, making it difficult to wake up the sleeper. Breathing becomes regular, blood pressure falls and the heart slows to 30% of its waking rate. The pituitary gland releases growth hormone at the beginning of this stage which stimulates tissue growth and muscle repair. Proteins in the blood that activate your immune system also increase, helping build the body’s defenses against illness and infection. Interesting side note here: People in young adulthood have many stretches of deep sleep, while those over 65 have none.

Enter now the fourth stage of sleep or dreaming sleepwhere the eyes dart back and forth rapidly behind your closed lids ( this is where the acronym REM comes from standing for “rapid eye movement”) and the brain races with thoughts and “dreams. Your body temperature and blood pressure rise, and your heart rate and breathing speed up to daytime levels. What is interesting is that the sympathetic nervous system, our fight-or-flight response, is twice as active as when we are awake. Despite all this activity, the body hardly moves, except for intermittent twitches. The rest of the muscles not needed for breathing or eye movement are essentially paralyzed. A normal night’s slumber consists of 3 to 5 approximately 90 minute periods of REM, but as we age they get shorter. Many scientists feel this is the time when the mind restores itself, which is important for cognition and memory. Early research into the role of REM sleep in-utero indicated that the rapid firing of nerve cells during this period was important for the growth and development of nerves. Subsequent studies on adult humans found that REM sleep deprivation led to poor performance on a variety of recall tests or logical tasks. In addition, memory loss occurred when sleep was deprived on the same night or two nights after the material had been learned and especially when subjects had been selectively deprived of one of the first two or last two REM episodes of the night. In other studies, REM cycles were found to increase after complex material had been studied, indicating that the brain uses this time to sort and process information into its memory banks. Other scientists suggest that REM sleep functions to dispose of unwanted memories through a mechanism called reverse learning. Reverse learning operates during this period of sleep to prevent the brain from being overloaded with massive amounts of information stored during wakefulness. A fine explanation for the insane dreams one may have, but testing this is pretty difficult, so it’s just a theory.

If your sleep is going to be interrupted, you do not want it to be during your stage 3 and stage 4 cycles. Overtime, deprivation of these levels of restorative sleep will take a toll on your outward appearance and your internal health, mentally and physically. Dermatologists have noted that collagen production increases during sleep, strengthening the bond between your exterior and deeper skin layers and allowing for the water retention necessary for suppleness. Also, growth hormone gets released in deep sleep, as mentioned earlier, which builds and repairs tissue. Without it, water evaporates from the skin leading to a dry, sallow complexion and the appearance of fine lines. Keep it up and skin could react with rashes and eczema. Lack of deep sleep increases the amount of inflammatory proteins in the blood and decreases immune system response. The more deprived you are, the more likely it will be that your body will react to pathogens and itself. The increased inflammatory proteins can lead to such conditions as heart disease and overall, research has indicated that people who get less than 6 hours of rest a night tend to have a higher mortality rate than those getting the recommended 7-8 hours. If you are a person who weight trains or exercises a lot, the lack of deep sleep does not allow for muscles to repair themselves and grow properly. This negates the affects of the workout and leaves them prone to injury. Outside memory loss, deprivation of REM sleep can lead to a diminished awareness of one’s surroundings, a severely reduced response time and an inability to perform tasks that are highly involved, such as driving or operating machinery. Far beyond drinking and drug use, lack of sleep is responsible for most of the accidents that occur on America’s roadways.

If you are having trouble getting to sleep at night, some of the obvious culprits could be stress, use of electronic equipment before bed, drinking too much caffeine and eating a big meal or going to bed hungry. Those have easy solutions, relatively speaking. You can get a massage, meditate or do some yoga to relax your body and bring your mind down from its stressful state. Have your coffee earlier in the day and cut down on the amount. No eating of large meals or snacks within 2 hours of going to bed, so you have ample time to digest. Shut the computer and the television and get them away from the area dedicated for sleepy time. Plunge yourself into darkness (remember that melatonin) and relative warmth, and sleep should come to you. However, there are some not so obvious culprits for disturbance of sleep. Check these out:

Taking a B vitamin supplement before bed – The B’s are super important for stimulating the nervous system, so popping supplements before bed can lead to fidgeting and constant awakening because the brain is way too “ON” to enter deep sleep.

Having a few drinks in your system – While it might get you to sleep faster, alcohol impedes the natural cycling of sleep stages, plunging you into what feels like deep sleep right away, but wearing off in the second half of the night when your REM cycles start kicking in. Since you never get to REM, you wake up more often than not feeling groggy, achy and depending on how much you drank, possibly still drunk.

Taking Prescription medications – Consider that sleep disturbance is a common side affect of some high blood pressure pills, birth control pills, steroids (including asthma inhalers), diet pills, antidepressants and cough and cold medications.

Smoking – Nicotine is a stimulant like caffeine so depending on how much you smoke and for how long, sleep can be dramatically reduced.

Working out at night – Some work schedules do not allow for morning or midday exercise, so many people will go to the gym after work. Exercise raises epinephrine levels in the blood, which makes us more alert and overall body temperature. These 2 factors can prevent sleep.

Hormonal changes – Long before menopause has kicked in, many women find they wake up in the night numerous times. This is due to fluctuating levels of estrogen and progesterone. Some younger women suffer from erratic sleep patterns before or during their menstrual cycles due to imbalances of these hormones.

Sleeping in on the weekends – It’s good for the circadian rhythm to awaken and go to sleep around the same times each day, but many of us tend to stay up later and sleep in more on days off. This throws off your internal clock, making it harder to fall asleep and awaken when faced with your normal schedule. Doctors suggest to sleep no longer than an hour more than you normally would in order to maintain the cycle.

Lastly, if you are chronically deprived of sleep despite your best efforts you should really think about visiting a doctor and/or finding a sleep clinic in your area to better assess and diagnose your problem. Now, go get a heaping helping of rest please!